Introduce a separate test module to validate functionality in controlled
scenarios.
The module provides a proc interface (/proc/kstackwatch_test) that allows
triggering specific test cases via simple commands:
echo test0 > /proc/kstackwatch_test
Test module is built with optimizations disabled to ensure predictable
behavior.
Signed-off-by: Jinchao Wang <wangjinchao...@gmail.com>
---
mm/Kconfig.debug | 10 ++++
mm/kstackwatch/Makefile | 6 ++
mm/kstackwatch/test.c | 122 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 138 insertions(+)
create mode 100644 mm/kstackwatch/test.c
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index 89be351c0be5..291dd8a78b98 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -317,3 +317,13 @@ config KSTACK_WATCH
A lightweight real-time debugging tool to detect stack corrupting.
If unsure, say N.
+
+config KSTACK_WATCH_TEST
+ tristate "KStackWatch Test Module"
+ depends on KSTACK_WATCH
+ help
+ This module provides controlled stack corruption scenarios to verify
+ the functionality of KStackWatch. It is useful for development and
+ validation of KStackWatch mechanism.
+
+ If unsure, say N.
diff --git a/mm/kstackwatch/Makefile b/mm/kstackwatch/Makefile
index 84a46cb9a766..d007b8dcd1c6 100644
--- a/mm/kstackwatch/Makefile
+++ b/mm/kstackwatch/Makefile
@@ -1,2 +1,8 @@
obj-$(CONFIG_KSTACK_WATCH) += kstackwatch.o
kstackwatch-y := kernel.o stack.o watch.o
+
+obj-$(CONFIG_KSTACK_WATCH_TEST) += kstackwatch_test.o
+kstackwatch_test-y := test.o
+CFLAGS_test.o := -fno-inline \
+ -fno-optimize-sibling-calls \
+ -fno-pic -fno-pie -O0 -Og
diff --git a/mm/kstackwatch/test.c b/mm/kstackwatch/test.c
new file mode 100644
index 000000000000..1ed98931cc51
--- /dev/null
+++ b/mm/kstackwatch/test.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/prandom.h>
+#include <linux/printk.h>
+#include <linux/proc_fs.h>
+#include <linux/random.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+
+#include "kstackwatch.h"
+
+static struct proc_dir_entry *test_proc;
+
+#define BUFFER_SIZE 16
+#define MAX_DEPTH 6
+
+struct work_node {
+ ulong *ptr;
+ struct completion done;
+ struct list_head list;
+};
+
+static DECLARE_COMPLETION(work_res);
+static DEFINE_MUTEX(work_mutex);
+static LIST_HEAD(work_list);
+
+static void test_watch_fire(void)
+{
+ u64 buffer[BUFFER_SIZE] = { 0 };
+
+ pr_info("entry of %s\n", __func__);
+ ksw_watch_show();
+ ksw_watch_fire();
+ pr_info("buf[0]:%lld\n", buffer[0]);
+
+ barrier_data(buffer);
+ pr_info("exit of %s\n", __func__);
+}
+
+
+static ssize_t test_proc_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *pos)
+{
+ char cmd[256];
+ int test_num;
+
+ if (count >= sizeof(cmd))
+ return -EINVAL;
+
+ if (copy_from_user(cmd, buffer, count))
+ return -EFAULT;
+
+ cmd[count] = '\0';
+ strim(cmd);
+
+ pr_info("received command: %s\n", cmd);
+
+ if (sscanf(cmd, "test%d", &test_num) == 1) {
+ switch (test_num) {
+ case 0:
+ test_watch_fire();
+ break;
+ default:
+ pr_err("Unknown test number %d\n", test_num);
+ return -EINVAL;
+ }
+ } else {
+ pr_err("invalid command format. Use 'testN'.\n");
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+static ssize_t test_proc_read(struct file *file, char __user *buffer,
+ size_t count, loff_t *pos)
+{
+ static const char usage[] = "KStackWatch Simplified Test Module\n"
+ "============ usage ==============\n"
+ "Usage:\n"
+ "echo test{i} > /proc/kstackwatch_test\n"
+ " test0 - test watch fire\n";
+
+ return simple_read_from_buffer(buffer, count, pos, usage,
+ strlen(usage));
+}
+
+static const struct proc_ops test_proc_ops = {
+ .proc_read = test_proc_read,
+ .proc_write = test_proc_write,
+};
+
+static int __init kstackwatch_test_init(void)
+{
+ test_proc = proc_create("kstackwatch_test", 0600, NULL, &test_proc_ops);
+ if (!test_proc) {
+ pr_err("Failed to create proc entry\n");
+ return -ENOMEM;
+ }
+ pr_info("module loaded\n");
+ return 0;
+}
+
+static void __exit kstackwatch_test_exit(void)
+{
+ if (test_proc)
+ remove_proc_entry("kstackwatch_test", NULL);
+ pr_info("module unloaded\n");
+}
+
+module_init(kstackwatch_test_init);
+module_exit(kstackwatch_test_exit);
+
+MODULE_AUTHOR("Jinchao Wang");
+MODULE_DESCRIPTION("Simple KStackWatch Test Module");
+MODULE_LICENSE("GPL");
--
2.43.0
